Four-year data after pediatric renal transplantation: a randomized trial of tacrolimus vs. cyclosporin microemulsion

Data mining and safety analysis of traditional immunosuppressive drugs: a pharmacovigilance investigation based on the FAERS database

OBJECTIVE

The purpose of this study aimed to explore the new and serious adverse events(AEs) of Tacrolimus(FK506), cyclosporine(CsA), azathioprine(AZA), mycophenolate mofetil(MMF), cyclophosphamide(CTX) and methotrexate(MTX), which have not been concerned.

METHODS

The FAERS data from January 2016 and December 2022 were selected for disproportionality analysis to discover the potential risks of traditional immunosuppressive drugs.

RESULTS

Compared with CsA, FK506 has more frequent transplant rejection, and is more related to renal impairment, COVID-19, cytomegalovirus infection and aspergillus infection. However, CsA has a high infection-related fatality rate. In addition, we also found some serious and rare AE in other drugs which were rarely reported in previous studies. For example, AZA is closely related to hepatosplenic T-cell lymphoma with high fatality rate and MTX is strongly related to hypofibrinogenemia.

CONCLUSION

The AEs report on this study confirmed that the results were basically consistent with the previous studies, but there were also some important safety signals that were inconsistent with or not mentioned in previous published studies.

EXPERT OPINION

The opinion section discusses some of the limitations and shortcomings, proposing the areas where more effort should be invested in order to improve the safety of immunosuppressive drugs.

Long-Term Outcome of Kidney Transplant Among Iranian Children: A Systematic Review and Meta-Analysis

OBJECTIVES

End-stage kidney disease has dramatic health effects and life consequences in children. Presently, kidney transplant has been globally accepted as a treatment of choice for end-stage kidney disease in both children and adults, leading to better quality of life and longer patient survival. Because of lack of comprehensive information on the outcome of kidney transplant among children in Iran, we aimed to present a proper vision of pediatric kidney transplant in Iran by systematically reviewing the current literature.

MATERIALS AND METHODS

Major databases were searched, including Medline, Web of Knowledge, Google Scholar, Scopus, Cochrane, and the Iranian Scientific Information Database for all eligible studies in accordance with specific keywords. The inclusion criteria for the retrieved studies were determination of graft survival, patient survival, and reasons for graft failure. The exclusion criteria were as follows: (1) a lack of clear results; (2) non-English or non-Persian language format; (3) lack of access to the full-text manuscripts; and (4) case reports, case series, and review papers. A total of 115 studies were initially assessed based on the keywords; of these, 8 met inclusion criteria and were considered for final analysis; these were published between 2005 and 2017.

RESULTS

According to our results, 1-year graft survival rates were overall 89.7%, and 5-year graft survival rates were 65.4%. The 1-year patient survival rates were estimated to be 97.1%, and 5-year patient survival rates were estimated to be 89.8%. Acute rejection, dialysis status before transplant, and inappropriate immunosuppression were the main risk factors.

CONCLUSIONS

Our systematic review and meta-analysis indicated a high success rate of childhood kidney transplant in Iran according to long-term graft and patient survival rates.

Immunosuppressants in Organ Transplantation

The goal of immunosuppressive therapy post-transplantation in pediatric renal transplant recipients is to prevent acute and chronic rejection while minimizing drug side effects. Most therapies alter immune response mechanisms but are not immunologically specific, and a careful balance is required to find the dose that prevents rejection of the graft while minimizing the risks of overimmunosuppression leading to infection and cancer. While this chapter because of space constraints focuses on immunosuppressive therapy in pediatric renal transplant recipients, many aspects can be applied on pediatric recipients of other solid organ transplants such as the liver and heart. The major maintenance immunosuppressive agents currently used in various combination regimens are tacrolimus, cyclosporine, mycophenolate mofetil, azathioprine, everolimus, sirolimus, and glucocorticoids (steroids). Although data from adult renal transplantation trials are used to help guide management decisions in pediatric patients, immunosuppressive therapy in pediatric renal transplant recipients often must be modified because of the unique dosage requirements and clinical effects of these agents in children, including their impact on growth and development. The optimal immunosuppressive therapy post-transplant is not established. The goal remains to find the best combination of immunosuppressive agents that optimizes allograft survival by preventing acute rejection while limiting drug toxicities.

Clinical aspects of tacrolimus use in paediatric renal transplant recipients

The calcineurin inhibitor tacrolimus, cornerstone of most immunosuppressive regimens, is a drug with a narrow therapeutic window: underexposure can lead to allograft rejection and overexposure can result in an increased incidence of infections, toxicity and malignancies. Tacrolimus is metabolised in the liver and intestine by the cytochrome P450 3A (CYP3A) isoforms CYP3A4 and CYP3A5. This review focusses on the clinical aspects of tacrolimus pharmacodynamics, such as efficacy and toxicity. Factors affecting tacrolimus pharmacokinetics, including pharmacogenetics and the rationale for routine CYP3A5*1/*3 genotyping in prospective paediatric renal transplant recipients, are also reviewed. Therapeutic drug monitoring, including pre-dose concentrations and pharmacokinetic profiles with the available "reference values", are discussed. Factors contributing to high intra-patient variability in tacrolimus exposure and its impact on clinical outcome are also reviewed. Lastly, suggestions for future research and clinical perspectives are discussed.

Converting immunosuppression from an oral suspension to a granule formulation of tacrolimus in pediatric renal transplant recipients

OS of tacrolimus prepared from tacrolimus powder is not licensed for children. A licensed GF for OS allows flexibility for body weight-based dose adjustments. This study aimed at exploring the efficacy of conversion from OS to the GF of tacrolimus in stable pediatric renal transplant recipients. Records of 25 pediatric renal transplant recipients aged under 18 years who were switched from an unlicensed tacrolimus OS to GF were reviewed. At day 0, 1 week, and 4-8 weeks post-conversion, there were no differences regarding daily tacrolimus dose (3.4 ± 3 vs 3.5 ± 2.9 vs 3.5 ± 2.9 mg/day), trough tacrolimus levels (4.5 ± 2.7 vs 4.2 ± 2.7 vs 4.4 ± 3.1 ng/mL), dose-normalized trough tacrolimus levels (1.7 ± 1.1 vs 1.5 ± 1.0 vs 1.7 ± 1.3 ng/mL/mg), PCr (65.6 ± 29.4 vs 67.9 ± 30.4 vs 69.8 ± 27.9 μmol/L), and eGFR (73 ± 24.9 vs 68.7 ± 20.2 vs 65.5 ± 18.2 mL/min/1.73 m² ) (P > .05). GF dose adjustment was required in 52% of participants. Eighty-eight percent of patients had to return for repeat tacrolimus levels following dose modifications, generating 33 extra visits (≥2 extra visits for 1/3 of subjects). No rejection episodes occurred in the year after conversion. In conclusion, conversion from tacrolimus OS to GF in stable pediatric renal transplant recipients is safe and efficacious. However, close therapeutic drug monitoring in the immediate post-conversion period is necessary.

Generic immunosuppressants

Immunosuppressive drugs for solid organ transplantation are critical dose drugs with a narrow therapeutic index. Many of the most commonly used innovator drugs are off patent and have been replicated by generic counterparts, often at substantial cost-savings to the patient. However, serious adverse events caused by the transition from innovator to generic medications, specifically in pediatric solid organ transplant recipients, have questioned these autosubstitutions. The purpose of this review is to summarize the criteria set forth by the regulatory bodies, and to examine how major immunosuppressive drugs conform to these recommendations. Regulatory bodies have established inconsistent criteria to demonstrate bioequivalence between innovator and generic medications, causing approved generic variations to have varying levels of equivalence with the innovator drugs. In order to minimize the risk for under-immunosuppression, the following recommendations have been concluded. Brand prescribing of cyclosporine and tacrolimus are recommended due to evidence of adverse events after conversion to generic formulations and differences in dissolution parameters. Mycophenolate mofetil (MMF) shows better bioequivalence between innovator and generic formulations, however caution should be advised when switching between formulations. The institution of 'innovator only' policies may be appropriate at this time in order to minimize the risk of under-immunosuppressing patients until the evidence of more stringent bioequivalence has been established.

Immunosuppressive therapy for kidney transplantation in children and adolescents: systematic review and economic evaluation

BACKGROUND

End-stage renal disease is a long-term irreversible decline in kidney function requiring kidney transplantation, haemodialysis or peritoneal dialysis. The preferred option is kidney transplantation followed by induction and maintenance immunosuppressive therapy to reduce the risk of kidney rejection and prolong graft survival.

OBJECTIVES

To systematically review and update the evidence for the clinical effectiveness and cost-effectiveness of basiliximab (BAS) (Simulect,(®) Novartis Pharmaceuticals) and rabbit antihuman thymocyte immunoglobulin (Thymoglobuline,(®) Sanofi) as induction therapy and immediate-release tacrolimus [Adoport(®) (Sandoz); Capexion(®) (Mylan); Modigraf(®) (Astellas Pharma); Perixis(®) (Accord Healthcare); Prograf(®) (Astellas Pharma); Tacni(®) (Teva); Vivadex(®) (Dexcel Pharma)], prolonged-release tacrolimus (Advagraf,(®) Astellas Pharma); belatacept (BEL) (Nulojix,(®) Bristol-Myers Squibb), mycophenolate mofetil (MMF) [Arzip(®) (Zentiva), CellCept(®) (Roche Products), Myfenax(®) (Teva), generic MMF is manufactured by Accord Healthcare, Actavis, Arrow Pharmaceuticals, Dr Reddy's Laboratories, Mylan, Sandoz and Wockhardt], mycophenolate sodium, sirolimus (Rapamune,(®) Pfizer) and everolimus (Certican,(®) Novartis Pharmaceuticals) as maintenance therapy in children and adolescents undergoing renal transplantation.

DATA SOURCES

Clinical effectiveness searches were conducted to 7 January 2015 in MEDLINE (via Ovid), EMBASE (via Ovid), Cochrane Central Register of Controlled Trials (via Wiley Online Library) and Web of Science [via Institute for Scientific Information (ISI)], Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects and Health Technology Assessment (HTA) (The Cochrane Library via Wiley Online Library) and Health Management Information Consortium (via Ovid). Cost-effectiveness searches were conducted to 15 January 2015 using a costs or economic literature search filter in MEDLINE (via Ovid), EMBASE (via Ovid), NHS Economic Evaluation Databases (via Wiley Online Library), Web of Science (via ISI), Health Economic Evaluations Database (via Wiley Online Library) and EconLit (via EBSCOhost).

REVIEW METHODS

Titles and abstracts were screened according to predefined inclusion criteria, as were full texts of identified studies. Included studies were extracted and quality appraised. Data were meta-analysed when appropriate. A new discrete time state transition economic model (semi-Markov) was developed; graft function, and incidences of acute rejection and new-onset diabetes mellitus were used to extrapolate graft survival. Recipients were assumed to be in one of three health states: functioning graft, graft loss or death.

RESULTS

Three randomised controlled trials (RCTs) and four non-RCTs were included. The RCTs only evaluated BAS and tacrolimus (TAC). No statistically significant differences in key outcomes were found between BAS and placebo/no induction. Statistically significantly higher graft function (p < 0.01) and less biopsy-proven acute rejection (odds ratio 0.29, 95% confidence interval 0.15 to 0.57) was found between TAC and ciclosporin (CSA). Only one cost-effectiveness study was identified, which informed NICE guidance TA99. BAS [with TAC and azathioprine (AZA)] was predicted to be cost-effective at £20,000-30,000 per quality-adjusted life year (QALY) versus no induction (BAS was dominant). BAS (with CSA and MMF) was not predicted to be cost-effective at £20,000-30,000 per QALY versus no induction (BAS was dominated). TAC (with AZA) was predicted to be cost-effective at £20,000-30,000 per QALY versus CSA (TAC was dominant). A model based on adult evidence suggests that at a cost-effectiveness threshold of £20,000-30,000 per QALY, BAS and TAC are cost-effective in all considered combinations; MMF was also cost-effective with CSA but not TAC.

LIMITATIONS

The RCT evidence is very limited; analyses comparing all interventions need to rely on adult evidence.

CONCLUSIONS

TAC is likely to be cost-effective (vs. CSA, in combination with AZA) at £20,000-30,000 per QALY. Analysis based on one RCT found BAS to be dominant, but analysis based on another RCT found BAS to be dominated. BAS plus TAC and AZA was predicted to be cost-effective at £20,000-30,000 per QALY when all regimens were compared using extrapolated adult evidence. High-quality primary effectiveness research is needed. The UK Renal Registry could form the basis for a prospective primary study.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013544.

FUNDING

The National Institute for Health Research HTA programme.

How randomised trials have improved the care of children with kidney disease

Randomised controlled trials (RCTs) provide the most reliable way to evaluate the benefits and harms of interventions. Participants are divided into groups using methods that balance the characteristics (both known and unknown) of the participants between treatment groups; thus, differences in outcomes are due to the interventions administered. From Cochrane Kidney and Transplant's Specialised Register, a comprehensive registry of trials in kidney disease, we identified 482 trials involving children. The vast majority concerned urinary tract infection (UTI; 134) and nephrotic syndrome (136). Most were small, with a median enrolment of 46 children, with only 26 trials enrolling 200 or more participants, and of these, 18 involved children with UTI. We discuss a number of important advances in the care of children with UTI with or without vesico-ureteric reflux, nephrotic syndrome, chronic kidney disease (CKD) and kidney transplantation that have been driven largely by trials in these conditions.

A preliminary study searching for the right dose of tacrolimus in very young (≤4 years) renal transplant patients

OBJECTIVES

The Radboudumc Amalia Children's hospital in the Netherlands has a programme for renal transplantation in children aged ≤4 years. Children receive chronic corticosteroid sparing immunosuppressive therapy that consists of tacrolimus and mycophenolate mofetil. This work aimed to describe the PK of tacrolimus in children ≤4 years with renal transplants.

METHODS

Paediatric renal transplant patients aged ≤4 years were included in this analysis. A PK curve of tacrolimus recorded ≤3 weeks after transplantation has been standard of care in our institution and aided in adjusting the dose in each patient to attain a target AUC_0-12h of 210 μg h/l early after transplantation.

KEY FINDINGS

Eight patients were included. The first two patients received an initial twice-daily regimen and the subsequent six patients a three-times daily regimen. Median dose-corrected AUC_tau was 63 μg h/l. AUC target attainment was 37.5%. Of the remaining patients, two had an AUC very close to (around 10% below) the target.

CONCLUSIONS

Large interindividual variability of tacrolimus was observed and showed suboptimal AUC target attainment. In this population, an even more aggressive approach of higher doses (e.g. 0.4 mg/kg per day) and more early AUC determination should be considered. This should be evaluated prospectively in a larger group of patients.

Relationship between mRNA expression levels of CYP3A4, CYP3A5 and SXR in peripheral mononuclear blood cells and aging in young kidney transplant recipients under tacrolimus treatment

Aim: The activity of several key enzymes involved in the metabolism of many drugs is subject to change closely related to the age of patients. This possibility must also be considered in the case of tacrolimus, the most important calcineurins inhibitor, which is widely used in pediatric kidney transplantation. As well as in the liver and intestine, some of the enzymes involved in the metabolism of tacrolimus were also isolated in the peripheral blood mononuclear cells (PBMCs), where also appear to play an important regulatory action. Therefore, the influence of some external factors on the expression of specific mRNA can be determined noninvasively. Patients & methods: The correlation between the levels of mRNA specific for key enzymes SXR, CYP3A and ABCB1 involved in the metabolism of tacrolimus was evaluated in PBMCs obtained from a selected population of 29 young kidney transplant recipients. A possible correlation between the expression of these specific mRNAs and tacrolimus pharmacokinetics was also investigated. Results: The patients’ age and their blood concentrations of SXR mRNA were directly correlated with the expression of CYP3A4, CYP3A5 mRNAs, but not of ABCB1 mRNA in the PBMCs. tacrolimus-normalized daily dose was strongly correlated with patient's age and multivariable regression indicates the CYP3A4-specific mRNA as the sole independent variable influencing tacrolimus concentration-to-dose ratio. Conclusion: Aging and SXR mRNA significantly affect the expression of CYP3A4- and CYP3A5-specific mRNA as measured by their concentration in PBMC.

Original submitted 17 November 2014; Revision submitted 6 February 2015

New-onset diabetes after kidney transplant in children

The development of new-onset diabetes after kidney transplantation (NODAT) is associated with reduced graft function, increased cardiovascular morbidity and lower patient survival among adult recipients. In the pediatric population, however, the few studies examining NODAT have yielded inconsistent results. Therefore, the true incidence of NODAT in the pediatric population has been difficult to establish. The identification of children and adolescents at risk for NODAT requires appropriate screening questions and tests pre- and post-kidney transplant. Several risk factors have been implicated in the pathogenesis of NODAT and post-transplant glucose intolerance, including African American race, obesity, family history of diabetes and the type of immunosuppressant regimen. Moreover, uremia per se results in a state of insulin resistance that increases the risk of developing diabetes post-transplant. When an individual becomes glucose intolerant, early lifestyle modification and antihyperglycemic measures with tailoring of the immunosuppressant regimen should be implemented to prevent the development of NODAT. For the child or adolescent with NODAT, antihyperglycemic therapy should be prescribed in order to achieve optimal glycemic control, ultimately reducing complications and improving overall allograft and patient survival. In this article, we review the risk factors, screening methods, diagnosis, management and outcome of children and adolescents with NODAT and post-kidney transplant glucose intolerance.

Peri-operative kidney injury and long-term chronic kidney disease following orthotopic heart transplantation in children

Significant advances in cardiac intensive care including extracorporeal life support have enabled children with complex congenital heart disease and end-stage heart failure to be supported while awaiting transplantation. With an increasing number of survivors after heart transplantation in children, the complications from long-term immunosuppression, including renal insufficiency, are becoming more apparent. Severe renal dysfunction after heart transplant is defined by a serum creatinine level >2.5 mg/dL (221 μmol/L), and/or need for dialysis or renal transplant. The degree of renal dysfunction is variable and is progressive over time. About 3-10 % of heart transplant recipients will go on to develop severe renal dysfunction within the first 10 years post-transplantation. Multiple risk factors for chronic kidney disease post-transplant have been identified, which include pre-transplant worsening renal function, recipient demographics and morbidity, peri-transplant haemodynamics and long-term exposure to calcineurin inhibitors. Renal insufficiency increases the risk of post-transplant morbidity and mortality. Hence, screening for renal dysfunction pre-, peri- and post-transplantation is important. Early and timely detection of renal insufficiency may help minimize renal insults, and allow prompt implementation of renoprotective strategies. Close monitoring and pre-emptive management of renal dysfunction is an integral aspect of peri-transplant and subsequent post-transplant long-term care.

Long-term outcomes of children after solid organ transplantation

Solid organ transplantation has transformed the lives of many children and adults by providing treatment for patients with organ failure who would have otherwise succumbed to their disease. The first successful transplant in 1954 was a kidney transplant between identical twins, which circumvented the problem of rejection from MHC incompatibility. Further progress in solid organ transplantation was enabled by the discovery of immunosuppressive agents such as corticosteroids and azathioprine in the 1950s and ciclosporin in 1970. Today, solid organ transplantation is a conventional treatment with improved patient and allograft survival rates. However, the challenge that lies ahead is to extend allograft survival time while simultaneously reducing the side effects of immunosuppression. This is particularly important for children who have irreversible organ failure and may require multiple transplants. Pediatric transplant teams also need to improve patient quality of life at a time of physical, emotional and psychosocial development. This review will elaborate on the long-term outcomes of children after kidney, liver, heart, lung and intestinal transplantation. As mortality rates after transplantation have declined, there has emerged an increased focus on reducing longer-term morbidity with improved outcomes in optimizing cardiovascular risk, renal impairment, growth and quality of life. Data were obtained from a review of the literature and particularly from national registries and databases such as the North American Pediatric Renal Trials and Collaborative Studies for the kidney, SPLIT for liver, International Society for Heart and Lung Transplantation and UNOS for intestinal transplantation.

Tacrolimus trough levels after month 3 as a predictor of acute rejection following kidney transplantation: a lesson learned from DeKAF Genomics

Most calcineurin inhibitor (CNI)-based protocols reduce blood trough goals approximately 2-3 months post-transplant in clinically stable kidney transplant recipients. The CNI target trough level to prevent rejection, after reduction, is unknown. Using a multivariate Cox proportional hazards model, we determined the association of time-varying tacrolimus (TAC) trough levels with acute rejection (AR) occurring in the first 6 months post-transplant, but specifically we assessed this association after 3 months. A total of 1930 patients received TAC-based immunosuppression prior to AR in a prospective study. Of the 151 (7.8%) who developed AR, 47 developed AR after 3 months post-transplant. In an adjusted time-varying multivariate model, each 1 ng/ml decrease in TAC trough levels was associated with a 7.2% increased risk of AR [hazards ratio (HR) = 1.07, 95% confidence interval (CI) (1.01, 1.14) P = 0.03] in the first 6 months. There was an additional 23% increased risk of AR with each 1 ng/ml decrease in the TAC trough levels in months 3-6 [HR = 1.23, 95% CI (1.06, 1.43) P = 0.008]. In conclusion, lower TAC trough levels were significantly associated with increased risk of AR in the first 6 months post-transplant with additional risk of AR between months 3 and 6 post-transplant. The timing and practice of TAC dose reduction should be personalized based on the individual's risk factors.

Outcomes of steroid-avoidance protocols in pediatric kidney transplant recipients

Advances in immunosuppression have facilitated increased use of steroid-avoidance protocols in pediatric kidney transplantation. To evaluate such steroid avoidance, a retrospective cohort analysis of pediatric kidney transplant recipients between 2002 and 2009 in the United Network for Organ Sharing database was performed. Outcomes (acute rejection and graft loss) in steroid-based and steroid-avoidance protocols were assessed in 4627 children who received tacrolimus and mycophenolate immunosuppression and did not have multiorgan transplants. Compared to steroid-based protocols, steroid avoidance was associated with decreased risk of acute rejection at 6 months posttransplant (8.3% vs. 10.9%, p = 0.02) and improved 5-year graft survival (84% vs. 78%, p < 0.001). However, patients not receiving steroids experienced less delayed graft function (p = 0.01) and pretransplant dialysis, were less likely to be African-American and more frequently received a first transplant from a living donor (all p < 0.001). In multivariate analysis, steroid avoidance trended toward decreased acute rejection at 6 months, but this no longer reached statistical significance, and there was no association of steroid avoidance with graft loss. We conclude that, in clinical practice, steroid avoidance appears safe with regard to graft rejection and loss in pediatric kidney transplant recipients at lower immunologic risk.

Posttransplant metabolic syndrome in children and adolescents after liver transplantation: a systematic review

During long-term follow-up, 18% to 67% of pediatric liver transplant recipients are overweight or obese, with rates varying by age and pretransplant weight status. A similar prevalence of posttransplant obesity has been seen in adults. Adults also develop posttransplant metabolic syndrome and, consequently, cardiovascular disease at rates that exceed the rates in age- and sex-matched populations. Posttransplant metabolic syndrome has never been studied in pediatric liver transplant recipients, and this population is growing as transplant outcomes continue to improve. Here we systematically review the literature for each component of metabolic syndrome-obesity, hypertension, dyslipidemia, and glucose intolerance-in pediatric liver transplant recipients. Their rates of obesity are similar to the rates in children in the general U.S. population. However, hypertension, dyslipidemia, and diabetes are more common than would be expected in transplant recipients according to age, sex, and obesity severity. Immunosuppressive medications are major contributors. The limitations of previous studies, including heterogeneous methods of diagnosis, follow-up times, and immunosuppressive regimens, hinder the analysis of risk factors. Importantly, no studies have reported graft or patient outcomes associated with components of metabolic syndrome after pediatric liver transplantation. However, if the trends in children are similar to the trends seen in adults, these conditions may lead to significant long-term morbidity. Further research on the prevalence, causes, and consequences of posttransplant metabolic syndrome in pediatric liver transplant recipients is needed and will ultimately help to improve long-term outcomes.

Intra-patient variability in tacrolimus trough concentrations and renal function decline in pediatric renal transplant recipients

High intra-patient variability in TCL exposure is a risk factor for allograft loss and late acute rejection. We hypothesized that a higher intra-patient variability leads to a faster decline in GFR in pediatric renal transplant patients and that adolescents have a higher intra-patient variability due to poorer adherence. We included 69 children aged 3.5-18 yr who had undergone renal transplantation between April 1996 and May 2009 in two pediatric nephrology centers in the Netherlands. We analyzed TCL trough concentrations over a period of one yr and calculated TCL trough concentrations variability using VC. We investigated the correlation between the TCL trough concentrations variability and the decline in estimated GFR over four yr. The median intra-patient variability in TCL concentrations was 30.1% (range 8.6-77.6) and the mean GFR slope -3.8 mL/min/1.73 m(2) /yr. The VC correlated neither with the GFR slope, nor with the patients' age. However, children with late acute rejection had higher VC (p = 0.045). We were unable to provide evidence that a high variability in TCL exposure leads to a faster decline in renal function, although children with late acute rejection have a higher variability in TCL exposure. Adolescents do not have a higher intra-patient variability in TCL trough concentrations than younger children.

Prophylaxis of chronic kidney disease after liver transplantation - experience from west China

AIM: To evaluate the prophylaxis of chronic kidney disease (CKD) after liver transplantation (LT) with low-dose calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF).

METHODS: From March 1999 to December 2009, a total of 572 patients (478 males and 94 females) underwent LT enrolled in the study. Initial immunosuppression was by triple-drug regimens that included a CNI, MMF, and prednisone. The initial dose of CNI was 0.05-0.10 mg/kg per day for tacrolimus (TAC) and 5-10 mg/kg per d for cyclosporine A (CSA) respectively, and was gradually reduced based on a stable graft function. The serum trough level of CNI was 6-8 ng/mL for TAC and 120-150 ng/mL for CSA 3-mo post-operation, 4-6 ng/mL for TAC and 80-120 ng/mL for CSA 1-year after transplantation was expected with stable liver function. MMF was personalized between 1.0-1.5 g/d. Glomerular filtration rate (GFR) was estimated by an abbreviated Modification of Diet in Renal Disease formula. Risk factors of CKD were examined by univariate and multivariate logistic regression.

RESULTS: With a definition of GFR < 60 mL/min per 1.73 m², the incidence of CKD was 17.3% 5-year after LT. There were 68.3% (293 of 429 cases) patients managed to control their TAC trough concentrations within 8 ng/mL and 58.0% (83 of 143 cases) patients’ CSA trough concentrations within 150 ng/mL. Of the 450 recipients followed-up over 1 year, 55.5% (183 of 330 cases) of which were treated with TAC had a trough concentration ≤ 6 ng/mL while 65.8% (79 of 120 cases) of which were treated with CSA had a concentration ≤ 120 ng/mL. The incidence of CKD in the groups of lower CNI trough concentrations was significantly lower than the groups with CNI concentrations above the ideal range. Patients with CKD had much higher CNI trough concentrations than that of patients without CKD. MMF was adopted in 359 patients (62.8%). Patients administrated with MMF had a relatively low CNI trough concentrations but with no significant difference. The graft function remained stable during follow-up. No difference was found between different groups of CNI trough concentrations. Pre-LT renal dysfunction, ages, acute kidney injury, high blood trough concentrations of CNI in 3 mo (TAC > 8 ng/mL, CSA > 150 ng/mL) and hypertension after operation were associated with CKD progression, while male gender and adoption of MMF were protection factors.

CONCLUSION: Low dose of CNI combined with MMF managed to prevent CKD after LT with stable graft function.

The importance of different immunosuppressive regimens in the development of posttransplant diabetes mellitus

Solid-organ transplantation is the optimal long-term treatment for most patients with end-stage organ failure. After solid-organ transplantation, short-term graft survival significantly improved (1). However, due to chronic allograft nephropathy and death with functioning graft, long-term survival has not prolonged remarkably (2). Posttransplant immunosuppressive medications consist of one of the calcineurin inhibitors in combination with mycophenolate mofetil (MMF) or azathioprine (Aza) and steroids. All of them have different adverse effects, among which posttransplant diabetes mellitus (PTDM) is an independent risk factor for cardiovascular (CV) events and infections causing the death of many transplant patients and it may directly contribute to graft failure (3). According to the criteria of the American Diabetes Association (4), diabetes mellitus (DM) is defined by symptoms of diabetes (polyuria and polydipsia and weight loss) plus casual plasma glucose concentration ≥ 11.1 mmol/L or fasting plasma glucose (FPG) ≥ 7.0 mmol/L or 2-h plasma glucose level ≥ 11.1 mmol/L following oral glucose tolerance test (OGTT). This metabolic disorder occurring as a complication of organ transplantation has been recognized for many years. PTDM, which is a combination of decreased insulin secretion and increased insulin resistance, develops in 4.9/15.9% of liver transplant patients, in 4.7/11.5% of kidney recipients, and in 15/17.5% of heart and lung transplants [cyclosporine A (CyA)/tacrolimus (Tac)-based regimen, respectively] (5). Risk factors of PTDM can be divided into non-modifiable and modifiable ones (6), among which the most prominent is the immunosuppressive therapy being responsible for 74% of PTDM development (7). Emphasizing the importance of the PTDM, numerous studies have determined the long-term outcome. On the basis of these studies, graft and patient survival is tendentiously (8) or significantly (9, 10) decreased for those developing PTDM.

Pediatric renal transplantation in the jordanian population: the clinical outcome measures during long-term follow-up period

INTRODUCTION

Recently, many international studies have suggested that pediatric patients from diverse ethnic origins confront unique challenges for transplantation. Data concerning the efficacy and safety of transplantation for various pediatric renal transplant populations remains limited and are often confounded by immunosuppressive protocols. In one study, we aimed to evaluate the short- and long-term outcomes of renal transplants in Jordanian children in comparison with groups of different nationalities.

METHODS

We retrospectively retrieved data for 34 Jordanian children who received kidney transplants from living donors between January 2003 and January 2009. Subsequently, we continued to follow-up with these selected patients at scheduled clinic visits to prospectively collect long-term data for a period of approximately 22 months±15 months.

RESULTS

The patients included in this study ranged between 4 years and 19 years of age. The male/female ratio was 0.79. Glumerulonephritis (35.3%) was the most common cause of end-stage renal disease in the sample of this study; 23.5% had received a preemptive transplant. All patients also received triple immunosuppressive therapy, consisting of tacrolimus (TAC), prednisolone, and mycophenolate mofetil (n=26) or azathioprine (n=8). Furthermore, the rate of acute rejection episodes was lower in the sample of this study than the average rate of many previous studies. The patients' survival rate at 1 year, 2 years and 3 years posttransplant was nearly 100%. The corresponding graft survivals were 97.1%, 94.12% and 91.2% respectively. Beyond three years, one female patient died postgraft loss. This graft loss was mainly attributed to recurrent glomerulonephritis. Strikingly, the prevalence of posttransplant diabetes (PTD) and hypertension was higher than reported international figures. Other adverse events, such as infections, were manageable.

CONCLUSION

The average result of pediatric renal transplantation in Jordan is more successful than the average results of this procedure in many developed countries, especially in terms of early graft function, acute rejection episodes as well as long-term patient and graft survivals. However, additional studies are needed to better characterize pharmacokinetic of TAC and to fully understand those factors that lead to an increased probability of developing conditions like PTD and hypertension.

[Immunosuppressive treatment]

Immunosuppressive treatment following renal transplantation includes induction therapy during the initial period when the risk of rejection is higher. Depleting anti-lymphocyte antibodies are indicated mostly in patients who developped anti-HLA antibodies and following a second graft. Anti-IL2 receptor antibodies may be used in non-responders. After the first month, maintenance therapy mostly consists in the association of several immunosuppressants, mainly corticosteroids, an antimetabolic agent (azathioprine or mycophenolate mofetil) and a calcineurin inhibitor (cyclosporine or tacrolimus). Side effects associated with these treatments led to the development of new immunosuppressive protocols, with the reduction or withdrawal of corticosteroids treatment due to its deleterious effects on statural growth, and decreased doses of anti-calcineurin agents to reduce their nephrotoxic effect. These therapeutic options are possible in patients at low immunological risk.

Minimizing steroid use in pediatric kidney recipients

Outcomes of pediatric kidney transplantation have improved significantly over the years, such that the majority of graft recipients survive to become adolescents and adults. In this article, the findings of some of the important trials that shaped the current therapeutic landscape of immunosuppression will be reviewed. As an evolving landscape, novel strategies are continuously being sought to address the significant challenges in pediatric transplantation. Among these challenges is the development of immunosuppressive strategies that not only minimize the risk of allograft rejection but also allow normal growth and developmental patterns in children. To that end, the growing clinical evidence that indicates that the use of steroid-sparing regimens is effective will be reviewed. Finally, a brief description of the TWIST study will be provided. This large-scale comparative study has been designed specifically to assess the effect of early steroid withdrawal on growth in pediatric renal transplant recipients. An overview of the preliminary analysis of the eagerly anticipated results of this landmark trial will also be provided.

Challenges in pediatric transplantation: the impact of chronic kidney disease and cardiovascular risk factors on long-term outcomes and recommended management strategies

Barriers to successful outcomes following pediatric transplantation have shifted from ischemic reperfusion injury and rejection to more long-term complications. Of particular concern is the high prevalence of CKD owing to preexisting damage and nephrotoxicity, as well as other CV complications such as hypertension and cardiomyopathy. All of these contribute to graft loss and shortened life expectancy, thereby limiting the success story of solid-organ transplantation. Managing CKD and related CV morbidity should be integral to the care of pediatric transplant patients, and timely detection of any irregularities would increase the chances of restoring lost kidney function. GFR is still the widely accepted indicator of renal function, and nuclear medicine techniques are the gold standard measurement methods. These methods are limited by costs, radiation exposure and substrate injection, and current practice still uses the Schwartz estimate, despite its well-documented limitations. Newer endogenous markers of GFR, such as cystatin C clearance, give a more accurate measure of true GFR but have not been embraced in the management of pediatric transplant recipients. Furthermore, indirect markers (e.g., microalbuminuria and hypertension) could also aid early detection of renal damage. The effects of mainstay immunosuppressants on kidney and heart function are varied, with available data indicating favorable outcomes with tacrolimus compared with ciclosporin. There is a need for appropriately designed and powered randomized controlled trials to validate innovative concepts for tailored immunosuppression in the pediatric population. To date, very few studies have generated long-term data in pediatric renal transplant patients - results of 1-4-yr study favored tacrolimus over ciclosporin, but other immunosuppressive agents also need to be evaluated.

Induction therapy in pediatric kidney transplant recipients discharged with a triple drug immunosuppressive regimen

We evaluated the effectiveness of induction therapy on transplant outcomes during 2004-2007 in the United States. We retrospectively reviewed OPTN/UNOS registry and selected kidney pediatric (<21-yr) recipients that received no induction (NoIND), IL-2RA, or rabbit anti-THY and were discharged with a triple drug immunosuppressive maintenance regimen, including steroids. Of 2932 recipients, 20%, 36%, and 43% were in NoIND, THY, and IL-2RA groups, respectively. The majority received tacrolimus (88%) and MMF (89%) at discharge. There was no association of induction with the risk of acute rejection even after adjusting for known cofounders. Compared to NoIND, IL2-RA, but not THY, had a modest decrease (3%) in absolute rate of graft loss and was associated with a risk reduction ratio of 0.51 (95% CI, 0.31-0.84) in one-yr graft loss. At three yr, no induction agent was associated with decreased graft loss. In conclusion, induction agents were used in 80% of pediatric kidney recipients discharged with a triple drug immunosuppressive maintenance regimen between 2004-2007 in the United States. Neither THY nor IL-2RA was associated with reduced rejection episodes. The use of induction therapy was not associated with improvement in three-yr graft survival.

Variables affecting estimated glomerular filtration rate after renal transplantation in children: a NAPRTCS data analysis

Short-term graft survival has improved in renal transplants without significant effect on long-term graft survival. As GFR decline precedes graft loss, an understanding of variables affecting eGFR after TX may help improve graft survival. NAPRTCS data were analyzed to assess effects of donor, recipient, and other variables on Schwartz eGFR after transplantation. For 8438 children with a functioning graft at day 30, data were censored for children dying with a functioning graft, and those with <3 yr follow-up. Multivariate linear regression and repeated measures analyses identified factors related to eGFR at day 30 after TX and during follow-up. Young, female, non-black, children without ATN and acute rejection in the first 30 days, TX after 1995, those with better eGFR at day 30, and receiving tacrolimus had better long-term eGFR. Transplant from ideal (6-35 yr) donors had best short-term eGFR, young donors (<5 yr) had lower eGFR and poor graft survival. After one yr, eGFR improved in surviving grafts of young donors and matched ideal donors. Acute rejection, BP medications, and hospitalizations in prior six months had negative association with subsequent eGFR. Regardless of variables, eGFR deteriorated with time. Slope of eGFR decline has not changed in the recent era indicating the need for innovative therapies.

Treatment strategies to minimize or prevent chronic allograft dysfunction in pediatric renal transplant recipients: an overview

Long-term allograft survival poses a major problem in pediatric renal transplantation, with allograft nephropathy being the principal cause of graft failure after the first post-transplant year. The mechanisms of nephron loss resulting in graft dysfunction are multiple, comprising both immunologic factors such as acute and chronic antibody- or T-cell-mediated rejection and non-immunologic components. The latter include peri-transplant injuries and renovascular lesions (renal artery stenosis, thrombosis) as well as cardiovascular risk factors such as arterial hypertension and hyperlipidemia. Another relevant issue leading to progressive nephron loss and declining kidney transplant function is acute and chronic nephrotoxicity induced by the calcineurin inhibitors (CNIs) ciclosporin (cyclosporine microemulsion) and tacrolimus. Furthermore, the presence of an abnormal lower urinary tract as well as bacterial (recurrent pyelonephritis) and viral (cytomegalovirus [CMV], polyomavirus [BK virus; BKV]) infections are crucial factors involved in the incidence of chronic allograft dysfunction and graft failure. Renovascular lesions and lower urinary tract obstruction are typical indicators for surgical intervention. The aim of treatment in pediatric patients with renal failure secondary to a dysfunctional lower urinary tract is to create a sterile, continent, and nonrefluxive reservoir. Surgical techniques such as bladder augmentation and the introduction of intermittent catheterization and anticholinergic therapy have significantly improved graft outcome. Arterial hypertension, another factor responsible for graft function deterioration in pediatric renal transplant recipients, is controlled preferably by the use of angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists, which are known to possess nephroprotective properties in addition to their potent antihypertensive effects. Although treatment of subclinical rejection with augmented immunosuppression has been associated with better graft survival, an increase of the immunosuppressive level to avoid subclinical rejection should be weighed against the risk of infection. The majority of viral infections affecting kidney allografts are caused by CMV and BKV. Antiviral CMV prophylaxis or pre-emptive therapy with ganciclovir has been shown to have beneficial effects in the pediatric renal transplant population. Treatment of BKV-induced nephropathy is based on reduction of the immunosuppressant therapy, although specific antiviral agents such as cidofovir and leflunomide are known to inhibit BKV. However, cidofovir itself is nephrotoxic and should therefore be administered cautiously to pediatric renal transplant patients. Since CNIs are likewise known for their nephrotoxic effects, especially with long-term use, alteration of the immunosuppressant regimen is necessary in case of deteriorating graft function due to CNI-induced histopathologic changes. Complete CNI avoidance seems inappropriate because, in this situation in pediatric renal transplant recipients, other relatively potent immunosuppressant agents such as lymphocyte-depleting antibodies, which are frequently accompanied by a higher incidence of infections, are needed for rejection prophylaxis. CNI withdrawal and switching of the immunosuppressant regimen from CNI therapy to sirolimus may be an option for some pediatric renal transplant patients with less advanced graft function deterioration. Nevertheless, potential adverse events such as aggravation of proteinuria, hyperlipidemia, myelosuppression, and hypergonadotropic hypogonadism have to be considered, and controlled studies are lacking. At present, an immunosuppressant maintenance therapy composed of low-dose tacrolimus or ciclosporin (CNI minimization) and mycophenolate mofetil with low-dose corticosteroids appears to be the most promising strategy to adopt in pediatric renal transplant recipients at low or normal immunologic risk.

Pharmacokinetics of tacrolimus in stable paediatric renal transplant recipients

Because tacrolimus (Tac) has a narrow therapeutic index and highly inter- and intra-individual variable pharmacokinetic (PK) characteristics, monitoring of drug exposure is recommended, but limited data are available on the kinetics of Tac in paediatric renal transplant recipients, especially of limited sampling strategies. To investigate the correlation between Tac trough level (TL) and the 0-12 h area under the curve (AUC), and the value of abbreviated AUC monitoring, we evaluated 12 h PK profiles in 27 children at least 1 year after transplantation. There was a significant discrepancy between Tac TLs and 0-12 h AUC (r = 0.60). Every time point, different from C(0), gave a better prediction for the drug exposure, with C(4) and C(6) as best predictors (r = 0.93 and r = 0.92, respectively). The 0-12 h AUC was estimated with great precision by the use of a two- or three-point sampling strategy, and the latter is more time-point independent. In paediatric renal transplant recipients on Tac maintenance therapy, whose condition is stable, Tac TL is not a reliable tool for the estimation of drug exposure. Abbreviated monitoring, especially at three points in time, give reliable predictions of the complete 0-12 h AUC. We suggest a 0-12 h AUC of around 150 ng x h/ml for stable paediatric renal transplant recipients 1 year after transplantation and around 100 ng x h/ml in the following years. Target AUC values should be further established for paediatric transplant recipients according to the time after transplantation.

Long-term outcome after renal transplantation in childhood

The purpose of this article is to review: 1. Factors influencing long-term outcome data after transplantation 2. Patient survival overall, the effect of recipient age and donor type, causes of death, comparison of mortality after transplantation with that on dialysis, and effect of pre-emptive transplantation and race 3. Transplant survival overall, and the effect of recipient and donor age, donor type, pre-emptive transplantation, recurrent diseases, human leukocyte antigen (HLA) matching, immunosuppression, concordance, hypertension, bladder dynamics and type of donor nephrectomy 4. Final height and obesity 5. Psycho-social outcome.

Multicentre prospective randomised trial of tacrolimus, azathioprine and prednisolone with or without basiliximab: two-year follow-up data

A total of 192 children and adolescents undergoing renal transplantation were randomly chosen to receive tacrolimus, azathioprine and corticosteroids (TAS, n = 93) or tacrolimus, azathioprine, corticosteroids and two doses of basiliximab (TAS + B, n = 99). Six-month outcome data have previously been reported; this manuscript reports the 2-year data. Complete 2-year data were available on 164 (85.4%) of the original 192 patients. There was a single death in the TAS arm. Kaplan-Meier estimates of survival free of graft loss at 2 years were 94.9% in the TAS + B arm and 89.6% in the TAS arm [hazard ratio (HR) 0.52; 95% confidence interval (CI) 0.17 to 1.54, P = 0.23]. Estimates of survival free from rejection at 2 years were 75.2% in the TAS + B arm and 68.7% in the TAS arm (HR 0.81; 95% CI 0.46 to 1.40, P = 0.44). The mean estimated glomerular filtration rate (GFR) at 2 years, was 65.8 ml/min per 1.73 m(2) body surface area in the TAS arm and 66.7 ml/min per 1.73 m(2) in the TAS + B arm (P = 0.78). Blood pressure and cholesterol levels were similar in the two arms, and there was no evidence of a difference in the incidence of infection or malignancy. These data provide further evidence of a lack of benefit associated with the addition of basiliximab to a TAS regimen for European paediatric renal transplant recipients at low immunological risk.

Urinary tract infections in children after renal transplantation

Urinary tract infections (UTI) after pediatric kidney transplantation (KTX) are an important clinical problem and occur in 15-33% of patients. Febrile UTI, whether occurring in the transplanted kidney or the native kidney, should be differentiated from afebrile UTI. The latter may cause significant morbidity and is usually associated with acute graft dysfunction. Risk factors for (febrile) UTI include anatomical, functional, and demographic factors as well as baseline immunosuppression and foreign material, such as catheters and stents. Meticulous surveillance, diagnosis, and treatment of UTI is important to minimize acute morbidity and compromise of long-term graft function. In febrile UTI, parenteral antibiotics are usually indicated, although controlled data are not available. As most data concerning UTI have been accumulated retrospectively, future prospective studies have to be performed to clarify pathogenetic mechanisms and risk factors, improve prophylaxis and treatment, and ultimately optimize long-term renal graft survival.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Avoiding steroids in pediatric renal transplantation: long-term experience from a single centre

We report our experience in pediatric renal transplantation avoiding steroids whenever possible. Immunosuppression consisted of an initial induction with antithymocyte globulin followed by maintenance therapy with a calcineurin inhibitor and MMF. Steroids were only given to selected patients because of the primary disease, recurrence, rejection, or PTLD. Thirty-four transplants grafted into 32 recipients between 1995 and 2005 were followed for a median of 3.5 yr (range 1-9.8). All patients survived. Graft rejection occurred in 10 cases during the first year post-transplantation and graft survival at one, five, and seven yr was 97, 88 and 88%, respectively. Steroids were given to half of the patients (n = 16); in nine cases due to rejection. Only four patients (13%) were continuously on steroids. Calculated GFR at one to five yr post-transplant were 73, 74, 68, 64, and 70 mL/min/1.73 m(2). Unfortunately PTLD occurred in three patients, but all survived with functioning grafts. Accordingly, our findings indicate that steroid avoidance in pediatric renal transplantation is possible with good results with respect to acute graft rejection as well as long-term graft survival.